On Fibonacci numbers with few prime divisors

If $n$ is a positive integer, write $F_n$ for the $n$th Fibonacci number, and $\omega(n)$ for the number of distinct prime divisors of $n$. We give a description of Fibonacci numbers satisfying $\omega(F_n) \leq 2$. Moreover, we prove that the inequality $\omega(F_n) \geq (\log n)^{\log 2 + o(1)}$ holds for almost all $n$. We conjecture that $\omega(F_n) \gg \log n$ for composite $n$, and give a heuristic argument in support of this conjecture.

Data and Resources

Additional Info

Field Value
Source Proceedings of the Japan Academy. Series A. Mathematical Sciences
Author Bugeaud, Yann, Luca, Florian, Mignotte, Maurice, Siksek, Samir
Maintainer CCSD
Last Updated May 9, 2026, 01:11 (UTC)
Created May 9, 2026, 01:11 (UTC)
Identifier hal-00088299
Language en
contributor Institut de Recherche Mathématique Avancée (IRMA) ; Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS)
creator Bugeaud, Yann
date 2005-05-09T00:00:00
harvest_object_id 32f4e842-228a-4293-9e26-5fa34eb43a97
harvest_source_id 3374d638-d20b-4672-ba96-a23232d55657
harvest_source_title test moissonnage SELUNE
metadata_modified 2025-06-04T00:00:00
set_spec type:ART